I prefer two overflows in a tank of that size and the flow your going to have. I always use a pair of 1 1/4in. in mine. If this was mine, I would use both bulkheads as overflows and run the return up and over the side.  
 
 Looks good otherwise. May have to watch the sand placement with the closed loop current. 
		
	
		
		
		
		
			
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				Doug
			 
		
		
		
		
	
		
		
	
	
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